Abstract

1. The sensitivity of various parts of the guinea pig's intestine to pilocarpine varies in the same way as the sensitivity of the dog's and cat's intestine to histamin as described by McKaye.

2. The duodenum and jejunum of the guinea pig contracted by histamin are relaxed by the addition of pilocarpine in concentrations as low as 1 part in 1,500,000. Further addition of histamin after this relaxation is without effect unless atropin is first added. The ileum is not relaxed by pilocarpine.

3. This confirms pharmacologically the results of several workers who have shown that electrical stimulation of the parasympathetics may under certain conditions cause gastro-intestinal relaxation.